Inexpensive multiple re-entry turbine



y 1965 c. E. MIDDLEBROOKS, JR 3,197,177

INEXPENSIVE MULTIPLE RE-ENTRY TURBINE Nb l0 L55 4- 26 b as l2 2 lab Wg-l IN V EN TOR.

y 7, 1965 c. E. MIDDLEBROOKS, JR 3,197,177

INEXPENSIVE MULTIPLE RE-ENTRY TURBINE Filed June 9, 1961 2 Sheets-Sheet 2 IN VEN TOR.

CLARENCE E.MIDDLEBROOKS, JR.

United States Patent 3,197,177 EJEXPENEZVE MULTIPLE REE-ENTRY TURBINE Cimeuee E. Middlehrooiis, Lira, 3807 Venice Drive,

Urlando, Fla. Filed .Iune 9, 1961, Ser. N 115,992 6 Claims. (Cl. 253-71) that such buckets must be constructed to withstand the high temperatures and high centrifugal forces imposed by turbine wheel use. Furthermore, conventional reentry designs are bulky, complex and require large envelopes due to the necessity of having recirculation tubes disposed about extensive portions of the turbine wheel housing. Because of the fact that conventional re-entry turbines require the motive fluid to always enter the blades from the same direction, this results in elongated recirculation ducts and attendant turning and drag losses resulting from the prolonged contact the high velocity fluid stream has with the recirculation ducts.

In the case of conventional wheels which incorporate multi-row, single stages within the embodiment, it is required that each of the bucket blades be equipped with intermediate shrouds in order to define the required separate flow passages along the blade length. This type design suiiers structural integrity and results in a bulky component which is expensive to manufacture and very vulnerable to thermal stresses, fatigue failure and inter stage leakage.

According to the present invention I utilize several techniques that are responsible for reducing the size and expense of turbines as well as substantially increasing the power and efficiency of a given size machine. My turbine wheel is advantageously constructed from left and'right wheel halves that are secured together with a number of buckets supported therebetween in the desired array. These buckets are manufactured from inexpensive thin-Wall round tubing bentto form short lengths of curved pipe, with a plurality of such buckets being disposed in a desired number of circumferential arrays about the wheel. A preferably cast stationary housing in winch the turbine wheel is operative may be equipped with a number of re-entry tubes that will redirect the hot gases leaving one bucket array into the bucket array located radially outwardly, or possibly radially inwardly therefrom if desired. Two, three or even a larger number of rows of buckets may be disposed upon a wheel, thereby representing a much larger active blade area, which will accommodate larger mass flows than is possible in prior art re-entry machines in which the gases flow through only a comparatively small circumferential arcuate portion of the turbine wheel. Not only does this arrangement enable all the available energy to be extracted from the motive fluids, but also only short re-entry tubes are required for the re-insertion of the gases leaving one row of blades into the next, outwardly or inwardly disposed row as the case may be, thereby minimizing the drag and thermal radiation losses that represent such a hi h percentage of waste in prior art machines.

Multi-staged machines according to this invention may utilize high pressure ratios and still retain the ad- 3,197,177 Patented July 27, 1965 vantages of low specific speed operation, and this in turn makes possible the direct coupling of a driven accessory to the turbine shaft, thus eliminating the need for reduction gearing with its accompanying cost and Weight.

One embodiment of this invention envisions the use of my low cost turbine in conjunction with a monofuel gas generator utilizing hydrogen peroxide, normal propyl nitrate, ethylene oxide or other monofuels. Such gas generator may be disposed in or adjacent to the hous ing so as to supply large quantities of motive fluid directly as in this case to the radially innermost array of buckets, re-entry tubes, as previously described, being responsible for re-inserting this motive fluid into subsequent stages of the Wheel in such manner as to extract a much larger percentage of the energy therefrom than is ordinarly possible, this being accomplished at a minimum of weight and internal loss. However, I am not to be limited to gas generators of this type inasmuch as it is within the spirit of my invention to also use solid propellant gas generators, air breathing systems, bi-propellant systems, compressed gas or steam as may be desired.

Other features may include the stage modulation of turbine power output by activating or de-activating a portion of the gas-injection nozzles, thus enabling each nozzle each nozzle and blade that is in use to operate at the design optimum aspect ratio and other internal aerodynamic design ratios which yield high. efiiciency to be maintained over a large range of mass flows or output power. a

It 'must be borne in mind that the foregoing advantages are obtainable without the necessity of using heavy or complicated fastening means for maintaining the turbine buckets in the desired positions, for my wheel design is such that the wheel halves define bucket supporting portions into which the buckets may be received, the displacement of the buckets from the desired position being prevented by the securing of the wheel halves together. Not only are the buckets of low cost, but also they provide a more suitable stream cross section for guidance than usual upon the hot gases impinging thereon, making possible the aforementioned multi-reentry, multi-single, or single stage arrangements within a minimum radial distance.

These and other objects, features and advantages will be apparent from a study of the enclosed drawings in which:

FIGURE 1 is a cross sectional view taken through the axis of a turbine according to my invention, revealing significant details or" the multi-stage. series type expansion techniques utilized herein, as well as one form of gas generator that may be used 7 FIGURE 2 is a view, partly in section, of a portion of the periphery of a turbine of the type shown in FIG URE l, revealing the pathway taken by ex-panding'gases as they successively pass through the various rows of blading; and

FIGURE 3 is a side elevational view with portions re moved to reveal the various radial locations at which the gas injection means are located.

Referring to FIGURE 1, a typical turbine arrangement 10 is there illustrated, comprising a housing 11 and a turbine wheel 12 rotatably mounted therein. Wheel 12 is principally constituted by a pair of wheel halves 12a and 12b which are secured upon rotatably mounted shaft 13 such as by splines 14 or the like. Wheel halves 12a and 12b, which may be formed through forging or casting techniques, are. configured to have a number of radially spaced circumferentially ex tending recesses disposed about the Wheel 12, with these recesses forming circumferential cavities when the wheel halves have been joined. Note in FIGURE 1 that the circumferential cavities 15, 16, and 17 are disposed at successively larger distances from the shaft 13. Bolts 18 or their equivalent are utilized to hold the wheel halves together.

The buckets for turbine wheel 12 are in the form of bent tubes disposed inthe cavities formed by and between the .wheel halves. Bucket 19, disposed in cavity 15 is representative of numerous buckets disposed in spaced relation about the wheel 12 in the position occupying the smallest wheel diameter, and it is this inner grouping of buckets that typically is arranged to receive the high pressure gases evolved from the gas generator used in conjunction with this invention. used in conjunction with this invention. Bucket 2%, disposed in cavity 16, is representative of the bucket array arranged to receive the gases that have already been expanded through the inner bucket array, and bucket 21, disposed in cavity 17 is representative of the bucket array through which the gases are finally expanded.

The buckets constituting the several spaced circumferential arrays are easily disposed and supported in the proper position according to this invention by virtue of a number of projections 22 disposed in spaced positions in circumferentially-extending recesses on each wheel half. As best seen in FIGURE 2, these projections are disposed at an angle to the juncture line between wheel halves, and are arrayed in aligned pairs about the wheel halves. Each projection incorporates a hollow entrance or exit into which the inner portions of the projections are drilled and reamed to produce tube receiving portions 23, otherwise referred to as bucket-supporting means. Thus, as seen in FIGURE 2, each tube of each group extends between the shoulders 23a defined at the inner ends of the tube receiving portions 23 of the projections 22, with the upper or outermost Walls of the three annular chambers or cavities 15, 16, and 17 serving to provide at some retaining effect upon the bucket; note FIGURE 3.

The housing 11 is preferably constituted by housing halves 11a and 11b which are secured together by peripheral bolts 24, located in bosses 25 closely spaced about the periphery of the housing. The central portion of each housing half is enlarged to form hubs 26a and 2611 which are appropriately drilled to receive bearing means, such as bearings 27a and 27]) illustrated in FIG- URE 1.

An oil seal 28 may be located on the end of shaft 13 from which power is extracted, with this seal being retained on the one side by snap ring 31, received in an appropriate circumferential recess in hub 26a. Wave spring 29 is employed between oil seal 28 and the outer race of annular contact bearing 27a to preload this bearing against shaft shoulder 13a. This in turn biases shaft shoulder 13b against annular contact bearing 27b. Inasmuch as the outer race of latter bearing is located in hub 26b by snap ring 32, it will be seen that bearings 27a and 27b are desirably preloaded to prevent skidding of the balls on the race ways during rapid acceleration of the shaft. Locknut serves to secure wheel 12 upon the splined shaft 13 and locate it in close contact with shaft shoulder 56. Carbon gas seal 33 is used to prevent the loss of gas pressure along the power-delivering end of shaft 13 whereas spherical plug 34 serves to enclose hearing 27!). A series of tapped holes 35 may be disposed about the concentric locating hub 26a for the mounting of gearboxes, driven equipment or accessories.

Housing halves 11a and 11b are formed so as to have appropriate gas directing means disposed therein. An integral gas generator 36 hereinafter described, may be used to supply high energy gas to the first stage buckets of wheel 12, these gases being supplied through a nozzle 37 formed in or otherwise integral with housing half 11b. Nozzle 37 is preferably of supersonic convergent-divergent configuration having a throat 53 which through choking establishes the correct mass flow through the turbine. The nozzle is illustrated in all three figures of the drawing with FIGURE 2 revealing that the center line of this nozzle bears an angle to the juncture line between wheel halves as do the projections 22, this angle being such that it reflects and satisfies the design requirements as would be evidenced by the appropriate tip speed to nozzle exit velocity vector diagram.

The gas entering through nozzle 37 impinges upon the buckets of the radially innermost array, in this instance the bucket 19 and other buckets located on the same radius. Gas leaving this array of buckets, rather than leaving the housing, is instead curved and redirected by re-entry tube 33 as illustrated in FIGURES 1 and 2, and re-inserted so as to impinge upon the array of buckets represented by bucket 26. Note this bucket in FIG- URES l and 2 representing the middle row of buckets. The gas leaving this middle array of. buckets is then curved and redirected by re-entry tube 39 so as to flow through the radially outermost bucket array represented -by bucket 21, where it undergoes its final expansion process. Exhaust diffuser 41 conducts the gas exiting from buckets 21 to the atmosphere or to a further device as may be desired. The diffuser 41 may be designed to cause discharged gases to over expand to a pressure less than the surrounding ambient pressure, thus resulting in a greater pressure differential across the turbine wheel, thereby yielding improved performance.

It should be noted that the present design advantageously reintroduces the high pressure gas into successive bucket stages without the heavy, cumbersome ducting required by prior art machines, which reintroduced the gas to the same buckets but at a different circumferential position. By the use of the present short re-entry tubes 38 and 39, the full advantage may be made of reentry techniques at the minimum weight as well as the minimum turning radius and drag losses. The blade area of my wheel is quite large in proportion to the diameter of the wheel and hence maximum horsepower can be extracted.

In addition to the above advantages, the costly buckets taught by the prior art are not required, but rather buckets constructed from inexpensive thin wall around tubing may be employed. As an example, the bucket arrays l9,"2il, and 21 may be constructed of nickel, chromium, cobalt, or other alloy steels for conventional applications and may have, for instance, /2 inch inner diameter and a inch wall thickness. After the tubes have been cut to proper length, they can be formed to the configuration shown in FIGURE 2 as an example by the use of conventional tube benders.

Since the bucket blade is for the most part entirely surrounded and supported by the inner details of the wheel discs 12a and 12b of which it is within, it is not essential that the tube material be of an alloy possessing premium strength properties at elevated temperatures. The use of high temperature cermets, ceramics, titanium or zirconium oxide tubes is possible within the spirit of this invention. These materials because of their poor structural properties could not be considered for conventional blading as taught by the conventional prior art. However, the blade supporting and retaining features of this invention do not bring about the creation of tensile stresses within the blade as were common to the prior art, thus allowing the use of these low strength ultra-high temperature materials, thus making feasible the operation of my turbine at turbine inlet gas temperatures of 3,000"- 6,000 F. It is well known that turbine operation in this temperature region yields high efficiencies, and specific fuel consumption approaches .4 lb./hp./hour on conventional open cycle schemes.

It is therefore to be seen that the required materials can be separated into two groups: the blading, which must possess the qualities of high melting point, low thermal conductivity and resistance to gas erosion, whereas the wheel halves must possess suitable tensile and creep properties, but in a substantially lower temperature range.

in certain embodiments it may be desirable to operate a device according to this invention at a temperature in which the blades are in a plastic condition, and in this instance it is desirable to fill the cavities 15, 16, and 17 with suitable fluid to a depth corresponding to the center line of tubes 19, Zti, and 21. For minimum blade stresses it is preferable that the fluid be of a density at or near that of the blade material, which fluid can either be a suitable metallic or a suitable non-'netallic fluid. Suitable metallic fluids are known as Na Ks, consisting of course of sodium and potassium. A typical non-metallic heat transfer-buoyant fluid preferred for this purpose is available under the trade name Dowtherm and is composed of 73.5% diphenyl oxide and 26.5% diphenyl. Thus it is to be seen that the buoyancy of the fluid in the chambers resists any attempted radial movement of the blades.

Fluid is prevented from leaking through the juncture of wheel halves either by applying a high temperature brazing material at such locations, or else by using pressure filled metallic rings or flexatallic type gaskets. As a further alternative, 2. cast wheel devoid of seams and joints, with the buckets cast in position may be used.

It may be desirable to cool one or more of the rows of chambers 16, and 17 and their related rows of tubular buckets 19, 2d, and 21. Either the metallic or the non-metallic fluid discussed hereinbefore can be used as the thermal courier or heat transfer medium.

Such fluid is delivered at a comparatively low temperature by means of a suitable pump or the like to an opening in the closure 34, and thence enters through an appropriate fitting into a passageway centrally disposed in shaft 13. This passageway preferably terminates short of the midpoint of the turbine wheel, turns, and goes radially outwardly, such as through a center portion of wheel half 1211. This passageway delivers relatively cool fluid to one or more of the cavities 15, for example, and in each cavity circulates thereabout and around the buckets 19 so as to absorb heat at a desired rate from the contacted surfaces. By regulating the temperature and flow rate of the fluid, the temperature of the working parts of the turbine wheel can be maintained at a design level.

Return passages extending radially inwardly through wheel half 12a, for example are provided to deliver the now-heated fluid back to a passageway located in the power-delivering end of shaft 13. Latter passageway is not connected with the aforementioned passageway in shaft 13 although these two passages are typically drilled so as to each be on the centerline of the shaft. Fluid ilowin from the return passageway is received by an appropriate receptacle from whence it is transported by appropriate fluid lines to the inlet of a heat exchanger device. Latter device is constructed to remove heat from the fluid before it is delivered to the inlet of the circulation pump mentioned hereinbefore, so that the fluid can be continuously reused.

The heat exchange device can be constructed to reject to a secondary fluid the B.t.u.s which represent the difference between inlet fluid enthalpy and exit fluid enthalpy, or alternatively the heat exchanger may be of the recuperator or regenerator type, in which event a great part of the rejected energy is re-introduced into the turbine ccle. This of course decreases the amount of fuel required to maintain a specific turbine inlet gas temperature, thus enhancing the operating efficiency and economy of a turbo machine constructed in accordance with my invention.

The assembly of the turbine wheel 12 may involve the insertion into one wheel half all of the buckets to be used in the wheel. These inserted buckets of course reside in the tube-receiving portion 23, contacting shoulders 23a 'of the projections 22. The two wheel-halves are then mated together in a spiral fashion so that the free end of each bucket is caused to enter the tube receiving portion 23 of the opposite wheel half. Then, upon the left and right wheel halves being moved into the final as sembled position, they are firmly secured together such as by the use of a number of bolts 13 that of course can be removed in the event that servicing or blade replacement is necessary. By proper sizing of the tubes so that they fit properly between the shoulders 23:: of the Wheel halves, there is little if any tendency for the buckets to move in an undesirable manner when the wheel halves have been finally secured together. However, it may be desirable to utilize additional means for securing the buckets in immovable positions such being in the form of protrusions 41} in the cavities against which the central portion of each bucket may rest, thus eflectively countering even very high centrifugal forces.

This invention is much broader than depicted by the drawings, for the scope of this invention comprehend-s the use of buckets of varying inner diameters, the particular diameter used for the buckets of each row being chosen so as to obtain a desiredamount of expansion in that row. The number of nozzles 37 employed may vary according to application, and may be located so as to serve only the innermost array of buckets or, the outermost array of buckets depending upon whether it is desired for the flow to be generally radially outwardly or radially inwardly. As another alternative, nozzles may be provided to supply motive fluid to each row of buckets in the event it is desired to reduce the number of re-entry tubes, or to eliminate entirely the use of same.

Gas generator 36 is secured adjacent housing 11, and in chamber 44 of this device large quantities of high pressure gases are evolved. These gases then flow through neck portion 47 and then through nozzle or nozzles 37 enroute to the buckets to react against same.

One or more atomizer nozzles 43 are provided to inject fuel into chamber :4 in proper quantities to sustain combustion. Droplets of fuel impinging upon electrically heated glow plug 45 are ignited, and once the combustion process has been initiated, it is self sustaining.

For simplicity, generator 36 is illustrated as a monofuel gas generator, in which may be used liquid monopropellants such as ethylene oxide, normal propyl nitrate or hydrazine. Decompostion of the fuel is initiated as the sprayed droplets exceed their autoignition temperature by coming into contact with the hot glow plug element. However, if monofuels such as nitromethane or hydrogen peroxide are used, catalytic initiators may be preferred.

The neck portion 47 of the gas generator and the nozzle 37 are each advantageously provided with flanges that together form a V flange 49. Encircling strap or band 4-8 is internally configured to fit closely about the abutting flanges, and when tightened, band 48 functions to hold the members 37 and 47 closely together.

However, any number of alternate gas generators may be preferred, in which case the band 48 is loosened to permit the desired substitution. For example, the steam discharge of either a firetube or a watertube boiler can be connected to nozzle 37 to cause steam to impinge upon the buckets of wheel 12. An alternative to this may be theuse of my turbine arrangement With a conventional bipropellant combustion chamber incorporating oxidizer and fuel atomization and injection means and may or may not incorporate a supplemental ignition device depending on whether or not the fuel-oxidizer combination is hypergolic in nature. Such a chamber would also have a hot gas discharge port attachment flange which would be compatible with, and could be attached to the V flange coupling 49. A typical storable hypergolic bi-propellant system would be RFNA (Red fuming nitric acid) and kerosene. A typical storable non hypergolic bi-propellant system might be N 0 (nitrogen tetra- Such oxide) and hydrazine. a system would require a supplemental ignition device or system.

In the event the turbine application was such that the use of a solid propellant system was desirable, the gas generator 36 would be replaced with a suitable breech. In this instance the breech would be of a suitable design to allow the loading of a suitable propellant grain (preferably of the composite end burning type) and would also incorporate provisions for ignition through the use of electrical initiated pyrotechnic squibs. It is preferred that said breech also be capable of allowing easy removal of expired squibs and cartridges, so that it could be reloaded for subsequent use. It is also desirable that the breech contain a chamber pressure relief device so as to allow control of the mass flow rate into the nozzle 37. A typical cartridge composition might incorporate potassium nitrate as an oxidizer and asphalt or rubber as a fuel; these being the principal constituents of the fuel.

It will also be apparent to anyone familiar with the art that my invention could also be operated with the use of compressed gas such as from a storage tank. In this instance the regulated gas would be ducted to the flange 49 by means of suitable tubing or pipe. A simple system of this type might utilize compressed air. An alternate system of this type offering'higher loading densities might incorporate a high pressure storage tank containing CO or Freon in the liquid phase and utilizing these gases at a lower pressure in the gaseous phase.

For extended operating cycles, or those applications requirin g minimum fuel consumptions, the monofuel chamber 36 would be replaced with a combustion chamber of the lassical design of those chambers utilized in the common open cycle gas turbine machines. Such a chamher would consist of an outer can containing within a perforated flame basket or inner liner, fuel atomizer nozzle, and ignition plug. Primary air as required to support combustion and secondary air for cooling are both furnished by a common compressor of either centrifugal or axial design or a combination thereof, the compressor being driven from a portion of the power delivered through the output shaft 13.

Various modifications within the spirit of this invention will be apparent to those skilled in this art. For example, I am not to be limited to turbine wheels made from left and right halves, for if desired wheels can be constructed in one piece, being cast about high. temperature buckets. Sand cores may be utilized to form the desired cavities and to prevent molten metal from flowing into the inside of said tubular buckets. The metal from which the wheel is cast would preferably be of an alloy containing molybdenum, tungsten, cobalt, chromium, nickel, or columbium. The casting technique utilized could be of conventional technology in which the metal is poured into the mold cavity in the liquid, molten state, or alternately, slip casting technology could be applied wherein powdered metal in suspension is introduced into the mold cavity in the cold state. mechanical pressures are applied to initially set, or fix the shaped casting. Sintering techniques are then utilized to bring about the desired increased density, particle fusion and crystalline structure of the wheel body.

Various other modifications within the scope of this invention will be apparent to those skilled in the design and construction of turbines and turbine wheels, and all modifications that come Within the meaning and range of equivalency of the appended claims are intended to be included therein.

I claim:

1. A turbine arrangement comprising a housing, a turbine wheel rotatably disposed in said housing, said wheel being constructed in two halves capable of being secured together to form the turbine wheel, the inner part of each wheel half having a plurality of radially-spaced circumferentially-extending recesses each containing a number of circumferentially-spaced bucket-supporting Next hydrostatic or means, the spacing of said bucket-supporting means being substantially identical so that when said wheel halves are secured together so that said recesses form cavities, said bucket-supporting means will be substantially aligned, buckets in the form of one-piece hollow curved tubes through which gas may flow, being disposed in said cavities between respective pairs of bucket-supporting means, said tubes being related to the size of their respective cavities such that each tube is restrained by the outermost wall of its cavity against undesired outward movement resulting from the centrifugal force developed during high-speed rotation, and injection means in said housing for injecting high-energy gas to impinge upon said buckets. thereby to propulsively drive said wheel in rotation, said cavities being substantially filled with metallic fluid, said fluid serving to provide additional support for said buckets at high. rotative speeds of said wheel thus enabling said buckets to resist radial displacement of said buckets.

2. The turbine wheel arrangement as defined in claim 1 in which redirecting means are disposed for re-inserting the gases emanating rom the first row of buckets into another row of buckets whereby to extract additional energy from said gases.

3. The turbine wheel arrangement as defined in claim 1 in which said buckets are formed from comparatively thin wall tubing.

4. The turbine arrangement as defined in claim 1 in which three circumferential rows of buckets are arrayed about the circumference of said turbine wheel, with each successive row being disposed at a larger radius than the preceding row, said gas injection means being disposed to inject high energy gases into the radially innermost row of buckets, and gas rc-directing means for re-injecting the high energy gases leaving from said first row of buckets into the middle row of buckets, and from the middle row of buckets into the outermost row of buckets thereby to effectively utilize the energy contained in said gas.

5. A turbine arrangement comprising a housing, a turbine wheel rota-tably disposed in said housing, and means for supplying quantities of compressed gas for causing rotation of said turbine wheel, said wheel being constructed from left and right halves with a comparatively large number of curved tubes of one-piece construction disposed in spaced relation in a plurality of circumferential arrays extending between said wheel halves, thus constituting at least two bucket arrays, each wheel half having a supporting means for said buckets, with a latter means being aligned so that each end of each bucket is supported in proper position by a Wheel half, means for securing said wheel halves together to prevent said buckets from becoming dislodged, said means for supplying compressed gas being arranged to inject gas to impinge upon a first circumferential array of buckets, and gas redirecting means in said housing for directing the gas leaving the first mentioned bucket array so as to cause it to impinge upon at least one subsequent bucket array located at a different radius on said wheel, each row of said buckets being disposed in an individual chamber in said turbine wheel, each of said chambers being at least partially filled with a metallic fluid, the fluid in each of said chambers being of a density approximately corresponding to that of the blade material, and furnishing a buoyancy serving to resist any tendency of said buckets to move radially under the effect of centrifugal force.

6. A turbine arrangement comprising a housing, a turbine wheel rotatably disposed in said housing, and means for supplying quantities of compressed gas for causing rotation of said turbine wheel, said wheel being constructed from left and right halves with a comparatively large number of curved tubes of one-piece construction disposed in spaced relation in a plurality of circumferential arrays extending between said wheel halves, thus constituting at least two bucket arrays, each wheel half having a supporting means for said buckets, with a latter means being aligned so that each end of each bucket is supported in proper position by a Wheel half, means for securing said wheel halves together to prevent said buckets from becoming dislodged, said means for supplying compressed gas being arranged to inject gas to impinge upon a first circumferential array of buckets, and gas redirecting means in said housing for directing the gas leaving the first mentioned bucket array so as to cause it to impinge upon at least one subsequent bucket array located at a different radius on said wheel, each row of said buckets being disposed in an individual chamber in said turbine wheel, each of said chambers being at least partially filled with a non-metallic, heat-transfer fluid, the fluid in each of said chambers being of a density approximately corresponding to that of the bucket material, and furnishing a buoyancy serving to resist any tendency of said buckets to move radially outwardly under the efiect of centrifugal force.

References (Iited by the Examiner UNITED STATES PATENTS 791,824 6/05 Schwarze 253--71 990,781 4/11 Ross 25371 996,3:24 6/11 De Ferranti 25371 X 1,194,507 8/16 Keppler 253-65 2,654,943 10/53 Campbell 29-156.8 2,800,706 7/57 Lindblom =291 56.8 2,841,362 7/58 Yeomans 253-69 FOREIGN PATENTS 237,475 9/ 45 Switzerland.

MARK NEWMAN, Primary Examiner.

SAMUEL LEVINE, Examiners. 

1. A TURBINE ARRANGEMENT COMPRISING A HOUSING, A TURBINE WHEEL ROTATABLY DISPOSED IN SAID HOUSING, SAID WHEEL BEING CONSTRUCTED IN TWO HALVES CAPABLE OF BEING SECURED TOGETHER TO FORM THE TURBINE WHEEL, THE INNER PART OF EACH WHEEL HALF HAVING A PLURALITY OF RADIALLY-SPACED CIRCUMFERENTIALLY-EXTENDING RECESSES EACH CONTAINING A NUMBER OF CIRCUMFERENTIALLY-SPACED BUCKET-SUPPORTING MEANS, THE SPACING OF SAID BUCKET-SUPPORTING MEANS BEING SUBSTANTIALLY IDENTICAL SO THAT WHEN SAID WHEEL HALVES ARE SECURED TOGETHER SO THAT SAID RECESSES FORM CAVITIES, SAID BUCKET-SUPPORTING MEANS WILL BE SUBSTANTIALLY ALIGNED, BUCKETS IN THE FORM OF ONE-PIECE HOLLOW CURVED TUBES THROUGH WHICH GAS MAY FLOW, BEING DISPOSED IN SAID CAVITIES BETWEEN RESPECTIVE PAIRS OF BUCKET-SUPPORTING MEANS, SAID TUBES BEING RELATED TTO THE SIZE OF THEIR RESPECTIVE CAVITIES SUCH THAT EACH TUBE IS RESTRAINED BY THE OUTERMOST WALL OF ITS CAVITY AGAINST UNDESIRED OUTWARD MOVEMENT RESULTING FROM THE CENTRIFUGAL FORCE DEVELOPED DURING HIGH-SPEED ROTATION, AND INJECTION MEANS IN SAID HOUSING FOR INJECTING HIGH-ENERGY GAS TO IMPINGE UPON SAID BUCKETS. THEREBY TO PROPULSIVELY DRIVE SAID WHEEL IN ROTATION, SAID CAVITIES BEING SUBSTANNTIALLY FILLED WITH METALALIC FFLUUID, SAID FLUID SERVING TO PROVIDE ADDITIONAL SUPPORT FOR SAID BUCKETS AT HIGH ROTATIVE SPEEDS OF SAID WHEEL THUS ENABLING SAID BUCKETS TO RESIST RADIAL DISPLACEMENT OF SAID BUCKETS. 